This Fish Katsu Curry takes a familiar favourite and turns it into something even more delicious and exciting. Swapping chicken for fish brings a new lightness and crispiness to the dish. It gets an extra layer of depth from caramelised onions – a small detail that makes all the difference. It brings a richness and depth of flavour that pairs beautifully with the golden, crispy fish fillets. Serve it with sushi rice and steamed vegetables for a complete, satisfying meal.
Table of Contents
- Ingredient Breakdown
- What Is Katsu?
- Why Panko is Non-Negotiable for Fish Katsu (or Any Katsu)
- Japanese Curry Block? What’s That?
- Taking Katsu Curry Sauce to the Next Level
- Fish Katsu Curry Serving Suggestions
- Want More Fish Recipes?
Ingredient Breakdown
- Vegetable oil: For frying the fish and sautéing the onions.
- Onions: Caramelised to add a rich, sweet base to the curry sauce.
- Garlic: Adds savoury depth to the curry sauce.
- Japanese curry block: A pre-made spice blend that delivers a complex curry flavour in one easy step.
- Boiling water: For dissolving the curry block and adjusting the sauce consistency.
- Plain flour: Helps create a solid base for the panko coating.
- Garlic and onion granules: Add a boost of flavour to the flour dredge for the fish katsu.
- Eggs: Help the panko adhere to the fish.
- Panko breadcrumbs: Japanese breadcrumbs that create a super crispy exterior.
- Hake fillets: A flaky white fish, perfect for frying.
What Is Katsu?
Katsu is a Japanese dish traditionally made with breaded and fried meat—most commonly pork (tonkatsu) or chicken (chicken katsu). The word “katsu” is a shortened version of the Japanese word katsuretsu, meaning cutlet.
What makes katsu so appealing? It’s all in the crispy coating. The use of panko breadcrumbs sets katsu apart from other breaded dishes, giving it a signature light, airy crunch without absorbing too much oil. While katsu can stand on its own, it’s usually paired with a tangy tonkatsu sauce or, in this Fish Katsu Curry, a rich curry sauce. The key is balance: the crunch of the katsu against the smooth, savoury sauce creates an unforgettable contrast.
Why Panko is Non-Negotiable for Fish Katsu (or Any Katsu)
You can’t make this Fish Katsu Curry without panko. Panko is essential for katsu because it delivers a light, crisp texture that regular breadcrumbs simply can’t match. Made from crustless bread and processed into larger, airier flakes, panko creates a crunch that’s not only crisp but stays light without soaking up excess oil. This is key for katsu, as the delicate balance between a crispy coating and tender, juicy interior is what makes the dish so irresistible. Regular breadcrumbs, by contrast, tend to be finer and denser, resulting in a heavier, oilier crust that lacks the signature crunch of a proper katsu. Panko is non-negotiable if you want that perfect, airy crispness.
The breading process in this Fish Katsu Curry recipe is straightforward but essential for achieving the right texture. First, dredge your fish in seasoned flour, which helps the egg and panko stick. Then dip it in whisked egg, ensuring the panko adheres well. Press the panko firmly onto the fish so it’s completely coated—this is how you get that perfect crunch.
Once your fish is breaded, fry it in hot oil. The oil should be heated to 180°C to ensure the fish cooks quickly and the panko crisps up without burning. Fry each piece for about 2 to 3 minutes per side, just enough time for the coating to turn golden and the fish to cook through.
Japanese Curry Block? What’s That?
The curry component in this Fish Katsu Curry is Japanese. Japanese curry is different from Indian or Thai curries. It’s milder, slightly sweet, and has a thick, comforting consistency. Pre-made curry blocks simplify the process of making Japanese curry at home. These blocks are a blend of flour, oils, spices, and flavourings, all pressed into convenient cubes. The one I recommend, S&B Golden Curry, dissolves into a smooth sauce when combined with water.
What makes the curry block particularly handy is how customisable it is. Want it thicker? Use less water. Fancy a more liquid sauce? Add a splash more. And if you’re looking for a bit of heat, a dash of chilli oil or a pinch of chilli flakes does the trick. This Japanese curry base offers a solid foundation for building flavours, especially when you introduce caramelised onions into the mix.
Taking Katsu Curry Sauce to the Next Level
Caramelised onions take this Fish Katsu Currysauce to the next level. Caramelising onions isn’t just about sweetness—it’s about unlocking the deep, savoury potential hidden within this everyday ingredient. When you cook onions slowly, their natural sugars develop, giving them a rich, golden hue and a mellow, slightly sweet flavour that perfectly complements the savoury notes of the curry sauce.
The process of caramelising onions is simple, but it requires patience. Start with thinly sliced onions, cook them on medium heat in a splash of oil, and give them time. It can take around 30 minutes for them to turn the light golden brown we’re looking for, but don’t rush it. Stir occasionally, and let the onions release their moisture and concentrate their flavour.
Once the onions are golden, add garlic to the pan and sauté for just a minute. Finally, add the Japanese curry block and boiling water. This is where the transformation happens. The curry block melts into the onion and garlic mixture, creating a rich, velvety sauce. If you want to enhance the sauce further, consider adding a splash of soy sauce for umami or a bit of sugar for balance.
Fish Katsu Curry Serving Suggestions
Fish Katsu Curry is a hearty dish, and it pairs best with simple sides that won’t overwhelm the flavours. Serve it over a bed of warm, fluffy sushi rice. The rice will soak up that rich caramelised onion curry sauce, adding a comforting element to the dish. For a pop of freshness and a bit of balance, add steamed vegetables like broccoli, sugar snap peas, or spinach.
If you want to make the dish even more special, why not serve it with a side of pickles? Japanese pickled vegetables (tsukemono) add a sharp, tangy contrast that cuts through the richness of the curry and the crispy fish.
Want More Fish Recipes?
I’ve been sharing lots of delicious fish recipes on my Instagram and TikTok in a series I’ve called Fantastic Fish. If you love this recipe, why not try some of the others in the series?
- Coconut Milk Poached Fish: Inspired by Southeast Asian flavours, this dish features tender, flaky white fish, gently cooked in a fragrant, aromatic coconut broth.
- Salt and Pepper Fish Nuggets: Chicken nuggets are great, but have you ever had fish nuggets? They’re just as delicious and satisfying, but they feel lighter.
- Crispy Sea Bass with Spring Onion and Ginger Oil: Despite only using 4 ingredients, this dish is packed with flavour. And as if that weren’t enough, it’s incredibly easy to make and comes together in less than 20 minutes.
- Coconut-Crusted Thai Curry Sea Bass: If you’re a fan of Thai flavours, you’re going to love this one. The fish is marinated in Thai red curry paste, before being encased in a coconut crust and fried to golden perfection.
- Roasted Salmon with Curry Leaf Butter: Roasted salmon, topped with a delicious 3-ingredient curry leaf butter.
Fish Katsu Curry
Chicken katsu curry is fantastic, but have you ever had a fish katsu curry? This is one extra special as it features a caramelised onion katsu curry sauce, which adds extra depth to the dish. Serve with sushi rice and steamed vegetables for a truly delicious fish dinner.
- Prep Time: 15 minutes
- Total Time: 50 minutes
- Yield: 4 1x
Ingredients
For the caramelised onion katsu curry sauce
- vegetable oil
- 2 onions, thinly sliced
- 2 large garlic cloves, very thinly sliced or minced
- 1 x 92g Japanese curry block, broken or cut into small pieces (I use the S&B brand)
- 750ml boiling water, or more (as preferred)
For the seasoned flour:
- 50g plain flour
- 1 heaped tsp garlic granules
- 1 heaped tsp onion granules
- 1 heaped tsp fine sea salt
For the rest of the fish katsu:
- 2 large eggs
- 100g panko (Japanese breadcrumbs)
- 4 hake fillets (or any flaky white fish fillets)
- 1 spring onion, thinly sliced, for garnishing (optional)
- cooked rice and Japanese pickles, to serve
Instructions
- Heat a splash of vegetable oil in a large saucepan set over a medium heat. Add the onion and season with salt and pepper.
- Cook, stirring occasionally, until softened and beginning to caramelise, around 30 minutes. The onions should be lightly golden, not deep golden brown.
- Add the garlic and cook, stirring frequently, for 1 minute, then add the Japanese curry block pieces and boiling water.
- Stir until the curry block pieces are fully dissolved, then cover and simmer for 5 minutes. Remove the saucepan from the heat and set aside until ready to use.
- Prepare your dredging station: 1) Combine the plain flour, garlic granules, onion granules and salt in a wide shallow bowl, ensuring everything is well combined. 2) Crack the eggs into a separate wide, shallow bowl. Season with salt and white pepper (if you don’t have any, black pepper is fine), then whisk to combine. 3) Place the panko in yet another wide, shallow bowl.
- Dredge 1 hake fillet in the seasoned flour, turning to coat on all sides and shaking off any excess. Then, dredge in egg, turning to coat on all sides and letting the excess drip back into the bowl. Finally, dredge in panko, pressing firmly to help it adhere and ensuring that there are no bare spots. Gently shake off any excess then transfer to a large plate or baking sheet. Repeat with the remaining hake fillets.
- Fill a large, deep frying pan or sauté pan halfway with vegetable oil. Set the pan over a medium-high heat and heat the oil to 180℃.
- Fry the fish katsu, flipping once halfway through, until golden brown and crispy, 2 to 3 minutes per side, then transfer to a kitchen towel-lined plate to drain.
- Reheat the katsu curry sauce over medium heat. This is where you can adjust it to your liking. If you’d like it thinner, simply add more water. If you’d like it saltier, add salt or soy sauce. And if you’d like it spicy, add chilli flakes or chilli oil.
- To serve, pour the caramelised onion katsu curry sauce over cooked rice and top with the fish katsu. Serve immediately.
Notes
Prepping the fish while the onions caramelise will drastically reduce the total time needed to make this recipe.
